Ultra‐high‐performance liquid chromatography tandem mass spectrometry method for the determination of gambogenic acid in dog plasma and its application to a pharmacokinetic study

A highly sensitive and rapid ultra‐high‐performance liquid chromatography–tandem mass spectrometry method was developed and validated for the determination of gambogenic acid in dog plasma. Gambogic acid was used as an internal standard (IS). After a simple liquid–liquid extraction by ethyl acetate, the analyte and internal standard were separated on an Acquity BEH C₁₈ (100 × 2.1 mm, 1.7 µm; Waters ) column at a flow rate of 0.2 mL/min, using 0.1% formic acid–methanol (10:90, v/v) as mobile phase. Electrospray ionization source was applied and operated in the positive ion mode. Multiple reaction monitoring mode with the transitions m/z 631.3 → 507.3 and m/z 629.1 → 573.2 was used to quantify gambogenic acid and the internal standard, respectively. The calibration curves were linear in the range of 5–1000 ng/mL, with a coefficient of determination (r) of 0.999 and good calculated accuracy and precision. The low limit of quantification was 5 ng/mL. The intra‐and inter‐day precisions (relative standard deviations) were <15%. The methodology recoveries were more than 66.63%. This validated method was successfully applied to a pharmacokinetic study after intravenous injection administration of gambogenic acid in dogs at a dose of 1 mg/kg. Copyright © 2014 John Wiley & Sons, Ltd.